Evaluation of a Nisin-Eluting Nanofiber Scaffold To Treat Staphylococcus aureus-Induced Skin Infections in Mice

Abstract

ABSTRACTStaphylococcus aureusis a virulent pathogen and a major causative agent of superficial and invasive skin and soft tissue infections (SSSTIs). Antibiotic resistance inS. aureus, among other bacterial pathogens, has rapidly increased, and this is placing an enormous burden on the health care sector and has serious implications for infected individuals, especially immunocompromised patients. Alternative treatments thus need to be explored to continue to successfully treat infections caused byS. aureus, including antibiotic-resistant strains ofS. aureus. In this study, an antimicrobial nanofiber wound dressing was generated by electrospinning nisin (Nisaplin) into poly(ethylene oxide) and poly(d,l-lactide) (50:50) blend nanofibers. Active nisin diffused from the nanofiber wound dressings for at least 4 daysin vitro, as shown by consecutive transfers onto plates seeded with strains of methicillin-resistantS. aureus(MRSA). The nisin-containing nanofiber wound dressings significantly reducedS. aureusXen 36 bioluminescencein vivoand viable cell numbers in a murine excisional skin infection model. The bacterial burden of wounds treated with nisin-containing nanofiber wound dressings was 4.3 × 102CFU/wound, whereas wounds treated with control nanofiber wound dressings had 2.2 × 107CFU/wound on the last day of the trial (day 7). Furthermore, the wound dressings stimulated wound closure of excisional wounds, and no adverse effects were observed by histological analysis. Nisin-containing nanofiber wound dressings have the potential to treatS. aureusskin infections and to potentially accelerate wound healing of excisional wounds.